Video Transcript
Which of the following statements does not accurately describe a comparison between nickel and sulfur? (A) Nickel has a higher melting point than sulfur. (B) Nickel is denser than sulfur. (C) Nickel is softer than sulfur. (D) Nickel is stronger than sulfur. Or (E) nickel is more ductile than sulfur.
We’re being asked to compare the properties of two elements, nickel and sulfur. So let’s start by working out where these two elements are on our periodic table. Nickel can be found in the d-block in the middle of the periodic table, while sulfur is found closer to the right-hand side. Remember that on the left-hand side of the periodic table, we find metals. And on the right-hand side, we find nonmetals, with the exception of hydrogen, of course, which is a nonmetal.
We can see from this that nickel is a metal, while sulfur is a nonmetal. So what this question is really asking is for us to compare a metal with a nonmetal. The question is also asking for the one statement which does not accurately describe a comparison between a metal and nonmetal. This means that we can expect four of our potential answers to be true and one to be false. And it’s this false answer which is the correct one.
So let’s start with (A) nickel has a higher melting point than sulfur. The properties of a metal or nonmetal are often due to the structure, so let’s remind ourselves of the structure of a metal and nonmetal. A metal is made up of a closely packed regular lattice of atoms. In between these atoms, there is a sea of delocalized electrons. Nonmetals have much more varied structures. They tend to involve covalent bonds and sometimes individual molecules. They also tend to have localized electrons as opposed to the delocalized electrons in a metal.
But how does this relate to the properties of our metal and nonmetal? The attraction between our positively charged nuclei and our negatively charged sea of electrons in a metal makes metallic bonding very strong. Because this structure is so strong, if we want to melt it, for example, we need an awful lot of energy. Because metals need a lot of heat to melt them, they have high melting points.
Remember, as well, that nonmetals often have the opposite properties of metals. Because the structures of nonmetals tend not to be anywhere near as strong as a metal, they have much lower melting points, since it takes a lot less energy to melt them. In fact, some nonmetals are even gaseous at room temperature, for example, oxygen. So answer (A) says that nickel, a metal, should have a higher melting point than sulfur, a nonmetal. And we’ve discovered that this is true. This means that (A) is not the correct answer.
Let’s move on to (B) that nickel is denser than sulfur. Density is a measure of how much mass there is in a certain volume. Metals have a closely packed regular lattice structure of the atoms. This means that they have a high density. Nonmetals, on the other hand, don’t always have lots of atoms in a small space. And nonmetals tend to have a low density. So the statement that nickel, a metal, has a higher density than sulfur, a nonmetal, is true. So again, this is not the right answer.
Statement (C) says that nickel is softer than sulfur. We’ve already seen that the metallic bonding in nickel is very strong, while the bonding in nonmetals is much weaker. This makes many nonmetals very soft. So the statement that nickel, a metal, is softer than sulfur, a nonmetal, is false. So this is a correct answer. But let’s check the last two statements just to be safe.
(D) says that nickel is stronger than sulfur. And we’ve already seen that this is true. Metals are stronger than nonmetals, so (D) is incorrect.
Statement (E) says that nickel is more ductile than sulfur. The word “ductile” means that a substance can be drawn out into wires. Metals are often ductile, again, because of the structure. When you apply a force to a metal, the layers of atoms can slide over one another. And this allows them to be drawn out into wires. This is the same reason that metals are malleable as well, where malleable means that a substance can be hammered into shape. So the statement that nickel, a metal, is more ductile than sulfur, a nonmetal, is true. Nonmetals are not ductile. They are, in fact, brittle, which means that if you try to deform them, they break.
So the only false answer and, therefore, the correct answer to our question is (C): Nickel is softer than sulfur.
